In various fields and applications, accurately determining the position of an object relative to a person holding or wearing the object, or the position of part of a person's body (e.g., a person's hand) relative to another part of the person (e.g., the person's head) is critical to successfully achieving a desired outcome. For example, virtual reality applications being developed today seek to render parts of a user's body, e.g., their arms and hands, within the digital world rendered by the application. The virtual reality application may show the person's arms and hands moving within the rendered digital world and interacting with virtual objects. Accurately determining the location and movement of the user's arms and hands would allow the virtual reality application to present a realistic experience to the user.
Accurately determining the position of part of a person's body relative to the person is also useful in the treatment of unconscious and unwanted behaviors, including the treatment of trichotillomania (hair-pulling disorder) excoriation (skin-picking disorder), nail biting and thumb sucking. Those who engage in these behaviors are often not aware that they are engaging in them. Studies have shown that if people are alerted when they are unconsciously engaging or about to engage in unwanted behaviors of this sort then they are less likely to engage in the unwanted behavior. Studies have shown that devices that provide this service can lead to long term, continual and independent cessation of the behavior.
Trichotillomania, also called hair-pulling disorder, is a mental disorder that involves recurrent, irresistible urges to pull out hair from the scalp, eyebrows or other areas of the body, despite efforts to stop. Hair pulling from the scalp often leaves patchy bald spots, which cause significant distress and can interfere with social or work functioning. People with trichotillomania may go to great lengths to disguise the loss of hair. For some affected people, trichotillomania may be mild and generally manageable. For others, the compulsive urge to pull hair is overwhelming or unconscious.
Excoriation disorder, also known as skin-picking disorder, involves repetitive and compulsive picking of skin which results in tissue damage. Episodes of skin picking are often preceded or accompanied by tension, anxiety, or stress. The region most commonly picked is the face. Most patients with excoriation disorder report having a primary area of the body that they focus their picking on. Complications arising from excoriation disorder include: infection at the site of picking, tissue damage, and septicemia. Damage from picking can be so severe as to require skin grafting.
Hair pulling, skin picking, nail biting, thumb sucking and similar unwanted manipulation of the body can all take place unconsciously. Studies have shown that making individuals more aware that they are participating in these behaviors greatly decreases their propensity to engage in these behaviors in the future. CBT (Cognitive Behavioral Therapy) and ACT (Acceptance and Commitment Therapy) are both used to treat harmful hair-pulling and skin-picking behavior, but are not always effective. The present inventive device can be used in conjunction with talk therapies to increase the effectiveness of treatment. Talk therapies tend to focus on conscious thought processes. The present inventive device provides a therapeutic intervention during or before unconscious pulling of the hair or picking of the skin, a situation in which introspection and reflective decision making encouraged by CBT cannot apply.
Thumb sucking is normal in babies and young children. In some cases, thumb sucking after age 5 is done in response to an emotional problem or other disorder, such as anxiety. Children who suck their thumbs often or with great intensity around age four or five, or those who are still sucking their thumbs at age 6 or later, are at risk for dental or speech problems. Prolonged thumb sucking may cause the teeth to become improperly aligned (malocclusion) or push the teeth outward. Unhealthy thumb sucking has been treated with a blocking device worn on the hand which physically impedes thumb sucking, as well as the application of a bad tasting substance applied to the thumb to dissuade thumb sucking. Both of these treatments may be uncomfortable or even painful to a child. Both of these treatments may also be outside the bounds of culturally acceptable child care.
There are devices in existence (such as HabitAware Liv™) which are worn around the wrist, use an accelerometer or other relative position sensor, detect gestures correlated to unwanted behaviors and provide vibrotactile feedback to the user, making them aware of the gesture. These devices may consist of the following components: a relative position sensor (accelerometer, gyroscope, magnetometer, etc.), a processing unit (microcontroller or System on Chip such as ARM Cortex family), and a radio transceiver such as a Bluetooth and a vibration motor. Examples of this combination and configuration of hardware components are activity trackers such as the FitBit™. The HabitAware Liv™ device essentially consists of the same mechanical and electrical parts as a commonly available activity tracker, such as the FitBit™, configured to detect a gesture of the hand (such as raising of the hand to unconsciously pull hair) instead of the steps taken during running or walking and other common activities. Similar configurations of sensors, processing units and feedback mechanisms exist to monitor sleep; in fact, the same device can sometimes be used to monitor walking and sleep. In many cases the device “syncs” or connects to a software program on a computer or smartphone, often connected to an internet platform or online “cloud” platform.
Prior devices that rely on accelerometers and other relative position sensors cannot “dead reckon” their position relative to another object. For example, the sensors may detect the angular position of the device relative to gravity, but they cannot detect whether the device is above, below or to the side of the user's head or any other object. There is therefore a need for improvements in devices that overcome some or all of the previously described drawbacks of prior options. The present inventive device differs from the HabitAware Liv™ and other prior devices by providing novel and inventive means to decrease false positive feedback, i.e, feedback that is mistakenly provided by the prior device when the target gesture is not taking place. The present inventive device further increases the likelihood of detecting unwanted behavior events which warrant feedback.